Replacing a regular switch with a dimmer switch is one of the easiest DIY electrical projects. In most cases, no permit or inspection is required, but it is important to be careful whenever working around electricity.
Safety Check: Is the Power Off?
Any time you’re working with electricity, be sure to turn the power off at the panel and follow these steps:
Check to be sure the circuit is dead by flipping the existing switch on and off before removing the switch plate. Once the plate is off, it’s a good idea to check the wires in the electrical box with a voltage tester, just to be sure. If there’s more than one switch or a receptacle in the same box, check the second device’s wires with the voltage tester as well. Sometimes more than one circuit feeds into the same box.
How to Wire and Install a Dimmer Switch
One difference between dimmer switches and regular switches is that with the latter, the house wires attach directly to the switch. Most dimmers, on the other hand, come with integral wire leads that connect to the house wires using wire nuts. Here is how to wire the new switch:
Make Sure Switches and Light Bulbs are Compatible
Not too long ago, the only dimmer switches you could buy were rheostats that reduced the amount of electricity going to the light by turning some of it into heat at the switch. Without delving too far into physics, the advent of semi-conductors has changed how modern dimmer switches control electricity. Dimmers no longer generate much heat and work by modifying the wave-form of how the power flows. The important thing to know when buying a dimmer switch now is what type of light it will control. Is it a compact fluorescent? LED? Halogen? Particularly with fluorescents and LEDs, it’s important to have dimmable bulbs as well as to have a dimmer switch that’s rated for that type of light. Read the manufacturer’s labeling carefully when buying light bulbs to make sure they will work with a dimmer switch. You’ll also need to check the capacity of the dimmer. If, for example, there are ten one-hundred-watt bulbs on that lighting circuit, the dimmer must be rated for at least 1000 watts.
What Are Three-Way Dimmers?
A three-way circuit controls a light from two locations and requires special switches. Four-way circuits are similar but control the light from three or more locations. Rather than using cable with two insulated wires (one black and one white) plus a bare ground, these circuits use cable with three insulated wires (black, white, and red) plus a bare ground. The main difference is that you have to pay close attention to the existing switch. One terminal on that switch will be black. The wire that leads to that black terminal must connect to the black wire on the new dimmer switch. Otherwise, the job is similar. Once you’ve put everything back together, flip the breaker back on and enjoy the new atmosphere you’ve created.
